1. Field of the Invention
The invention relates to a method and apparatus for switching data words among time slots, the data words being applied in time-division multiplex to a time switching stage, and a data word I.sub.s in a time slot s (s=0, 1, 2, ..., n-1) of an incoming frame comprising n data words in n time slot.sup.s being switched by the time switching stage to a time slot in an outgoing frame in which the data words I.sub.s have any other predetermined sequence D(s) D(s)=0, 1, 2, ..., n-1), the time switching stage comprising a memory for storing the data words.
2. Description of the Related Art
With the aid of time stages such as they are now used in switching systems for, for example, telephone exchanges, a number (N) of channels of identical capacities (C) are switched. To that end the time stage comprises inter alia a memory having a capacity of N words. For synchronously operated networks a memory capacity of N words is sufficient. If however the possibility must be created to switch N channels in plesiochronous networks whilst maintaining time slot integrity or if what are commonly referred to as multi-slot connections must be switched, then a memory having a larger (double) capacity must be available.
From European Patent Application No. EP 0012135 it is known to switch data words in the time slots of a PCM-frame bit-sequentially, the correct time sequence of the bits being guaranteed by delaying or not delaying the bits through a cycle period in the switching memory.